Why'd you have to die? Now George isn't gonna let me tend the rabbits :(
The men are outside the barn, spending their free time playing horseshoe. With each horseshoe the men would have a reaction, constantly cheering and shouting. This made it hard for the men to hear anything going on near them. For instance, they couldn't hear anyone inside the barn. However, the people in the barn could hear the men just fine.
This scene is taking place while the other men at the ranch are outside having fun and playing horseshoes. Lennie accidentally kills his pup, who he got from Slim, and is worried about George getting mad. George and Lennie have a dream, they want to own their own little house and one of the responsibilities Lennie wants is to tend the rabbits. However, George told him that if he did something bad he wouldn't get the opportunity to tent the rabbits.
Curley's Wife interrupts Lennies' mourning for his dog, (he hides the dog in the hay) and attempts to start a conversation with him. However, Lennie knows better than to talk to her. In the novel, George tells him multiple times that she's trouble, and all she'll do is cause them trouble. Unfortunately, Lennie begins to have a conversation with her. She tells him her dream of wanting to be an actor, and he responds with his dream of tending the rabbits <3
Curley's wife tells Lennie's to touch her hair, after he states he likes petting soft things. She doesn't want Lennie to mess it up, so she tells him to be careful. However, Lennie completely disregards her wishes, and ends up aggressively petting her hair. This freaks her out and she began to scream.
Trying to make Curley's wife be quiet, Lennie covers her mouth and swings her body around. Finally, she was quiet. He puts her down, but he realizes she died. Her neck snapped when he swung her around. Lennie knew he had just made a terrible mistake and remembered George told him to run into the brush, by the river.
Candy had walked into a barn, looking for Lennie. Instead, he find Curley's wife. He thinks she's sleeping and begins to talk to her. He tells her that seeing her sleeping gin the barn is really unusual. He finally realizes that she's dead and begins to freak out. He puts two and two together and figures out that Lennie had done this. Candy leaves to barn to find George.